1. Field of the Invention
The present invention relates to an electrical unit for a boat such as an engine control module for controlling engine operations and an outboard motor including the electrical unit.
2. Description of the Related Art
Conventional outboard motors have a configuration such that relays, fuses, branch-circuit components, an engine control module (hereinafter referred to as ECM), an operation time display section for measuring the engine operation time and so forth are positioned separately using wiring members such as a wire harness. Also, an operation time measuring device of a boat propulsion unit is known as disclosed in FIG. 8 in JP-B-2918887, in which an operation time displaying device (hour meter) is attached to mounting holes provided on the front wall of a CDI (Capacitor Discharge Ignition) so that it is visible from the front side (outside).
However, the invention described in JP-B-2918887 has problems and demands as described in the following three items below.
First, a relay, a fuse, and a branch-circuit component have the following problems on a conventional outboard motor.
The relay which drives a large current is separately disposed from an ECM, the branch-circuit component which branches a current or a signal is connected to a wire harness, and the circuit protection fuse is fixedly mounted to the wire harness. Therefore, this increases costs including the cost for the mounted components, operation costs, and the working hours required to mount the components.
Since the relay, the fuse, the branch-circuit component, an engine control module and so forth are provided at separate locations, a large space is required for mounting these components. Accordingly, an outboard motor, for example, becomes large and troublesome to transport or carry.
The wire harness connected to the branch-circuit component which divides a current or a signal must have waterproofing at its branch connecting point. However, insufficient waterproofing, fatigue from long use, or the like cause an electrical defect or a mechanical defect if contacted by water.
When a fuse circuit is incorporated as a separate component in an engine, a fuse connecting portion may be broken by vibration of the engine. In order to solve this problem, measures have been taken for reducing vibrations at a large cost. The cost is not small and tends to increase.
Second, on the other hand, an operation time display section has the following problems.
There are high costs for the mounting work and the components in order to make a construction to display an operation time of the engine by calculating from the number of revolutions of a generator or the like. This is because additional wiring in the outboard motor and additional components for mounting are needed. These extra costs make it difficult to lower the total cost to a user.
Furthermore, incorrect information is sometimes provided for a boat operator because the operation time display section is constructed to calculate the operation time by counting a pulse signal generated by the rotation of the generator which may pick up noise from the connection wiring and cause a malfunction.
Third, in the operation time display section, there are many cases in which simple mounting holes, simplified attaching to the mounting holes, reduced working hours, or reduced working costs are insufficiently achieved. Therefore, a solution to these problems is required.